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IC 9190 



Bureau of Mines Information Circular/1988 



Surface Testing and Evaluation 
of the Conveyor Belt Service 
Machine 



By Jasinder S. Jaspal and Lawrence F. Miller 



UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 9190 



Surface Testing and Evaluation 
of the Conveyor Belt Service 
Machine 



By Jasinder S. Jaspal and Lawrence F. Miller 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 
T S Ary, Director 



Library of Congress Cataloging in Publication Data: 



fN 



2 



°6 



UH 



r 



oA^° 



Jaspal, Jasinder 


S. 








Surface testing and evaluation of the conveyor belt service machine. 




(Information circular; 9190) 








Bibliography: p 


29. 








Supt. of Docs. 


no.: I 28.27:9190. 








1. Coal mines 


and mining— Equipment 


and supplies. 2. 


Mine 


haulage. 


3. Belt conveyors— Testing. I. Miller, L. 


F. II. Title, 


III 


Series: 


Information circular 


(United States. Bureau 


of Mines); 9190. 






TN295.U4 


[TN813] 622 


s [622'.66] 


88-600104 



CONTENTS 

Page 

Abstract 1 

Introduction 2 

Acknowledgments 3 

Design concept 3 

Description of the CBSM 4 

Structure 4 

Tractive system 4 

Hydraulic system 7 

Belt winding system 9 

Wire rope handling system 9 

Pneumatic system 9 

Work platform 10 

Belt-move extension procedure 11 

Belt-move retraction procedure 12 

Initial aboveground and underground testing and modifications 14 

Surface testing 15 

Test program overview 15 

Battery capability test 16 

Hydraulic system heat stabilization investigation 17 

Speed tests 19 

Braking tests 20 

Current draw test 21 

Controlled tension tests 21 

Static pull test 22 

Tram current test 22 

Tram duty cycle test 23 

Belt winder time study 25 

Summa ry 25 

Repairs and modifications 27 

Traction motor failure 27 

Tram electronics modifications 28 

Service brakes malfunction 28 

Hydraulic pump replacement 28 

Conclusions 28 

References 29 

Appendix A. — Conveyor belt service machine specifications 30 

Appendix B. — Conveyor belt service machine repairs and modifications 32 

ILLUSTRATIONS 

1. Conveyor belt service machine and associated belt-move equipment 4 

2. Conveyor belt service machine 5 

3. Conveyor belt service machine layout 5 

4. Conveyor belt service machine electrical schematic 6 

5. Operator tram control station 7 

6. Conveyor belt service machine hydraulic schematic 7 

7. Hydraulic control station 8 

8. Belt reel drive mechanism 8 

9. Belt reel 9 

10. Service machine belt storage capacity 10 

11. Left wire rope reel 10 

12. Air compressor 11 



11 



ILLUSTRATIONS— Continued 

Page 

13. Work platform 12 

14. Extension procedure 13 

15. Tailpiece hitch 13 

16. Tailpiece hitch adaptors 15 

17. Conveyor belt service machine battery capability tests 17 

18. Hydraulic pump and reservoir 18 

19. Heat stabilization test 20 

20. Tram duty cycle test course 24 

21. Belt winder system 26 

22. Belt pulled in ready to wind 26 

23. Wound belt 27 

24. Belt winder lock 29 

TABLES 

1. CBSM hydraulic heat stabilization test results 19 

2. CBSM speed test results 20 

3. CBSM braking test results 21 

4. CBSM current draw test results 21 

5. Belt winder controlled tension test results 22 

6. Belt winder static pull test results 23 

7. Tram current test results 23 

8. Tram duty cycle test results 24 

9. Belt winder time study results 25 





UNIT OF MEASURE 


ABBREVIATIONS USED 


IN THIS REPORT 


A 


ampere 


lb 


pound 


A/h 


ampere per hour 


Mm 


micrometer 


°F 


degree Fahrenheit 


mi/h 


mile per hour 


ft 


foot 


min 


minute 


f t 3 /min 


cubic foot per minute 


pet 


percent 


ft«lbf 


foot pound (force) 


psi 


pound (force) per square inch 


ft/s 


foot per second 


r/min 


revolution per minute 


gal 


gallon 


s 


second 


gal/min 


gallon per minute 


V 


volt 


h 


hour 


V dc 


volt, direct current 


hp 


horsepower 


yr 


year 


in 


inch 







SURFACE TESTING AND EVALUATION OF THE CONVEYOR 

BELT SERVICE MACHINE 

By Jasinder S. Jaspal 1 and Lawrence F. Miller 2 



ABSTRACT 

In underground room-and-pillar mining methods, the sectional conveyor 
belts are extended or retracted periodically to maintain shuttle car 
tramming distance to a minimum. A conventional conveyor belt extension 
or retraction is a heavy, arduous job that if mecahnized, has the poten- 
tial to improve productivity and safety. To reduce the burden of heavy 
work of this activity and mechanize it, the Bureau of Mines developed a 
conveyor belt service machine (CBSM) through a research contract with 
Tractor MBA. The CBSM is a self-contained, battery-powered, rubber- 
tired vehicle capable of handling, storing, and transporting conveyor 
belting, wire rope, and associated belt structures in seams as low as 48 
in. Belt extensions and retractions are accomplished by moving the 
tailpiece of a belt conveyor with the CBSM to the next position while 
dispensing or retrieving the belt, wire rope, and associated belt struc- 
tures. The CBSM improves the belt extensions and retractions by making 
them easier and faster, and it utilizes fewer workers. 

The CBSM was surface tested at the Bureau's Mining Equipment Test 
Facility (METF) to evaluate its performance and reliability. Modifica- 
tions were made to the CBSM to correct deficiencies found during surface 
testing. 

1 Mining engineer, Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 
^Deputy program manager, Boeing Services International, Mining Equipment Test 
Facility. 



INTRODUCTION 



Most of the coal produced in U.S. un- 
derground coal mines is moved by belt 
conveyors. A belt conveyor haulage sys- 
tem of a mine generally consists of a 
main line belt conveyor, section belt 
conveyor, and/or gathering belt convey- 
ors. In room-and-pillar mining opera- 
tions, shuttle cars carry coal from con- 
tinuous miners or loaders and unload it 
on the tailpiece of a section conveyor. 
The section belt is extended, by adding 
sections to the conveyor, as the face 
moves forward in order to keep the haul- 
age distance for the shuttle cars to a 
minimum. This ensures the maximum number 
of trips for shuttle cars in a shift, 
thus increasing the shift production. 
During retreat operations, the section 
belts are shortened by removing belt sec- 
tions from the section belt in keeping 
ahead of the retreat operation. 

The task of extension or retraction is 
referred to as a belt move. The section 
belt tailpiece is readily movable. A 
normal belt move requires six to eight 
workers and takes 3 to 8 h. A 100-ft 
belt move can require handling up to 
4,000 lb of materials. Since the belt 
move is a very labor intensive procedure, 
worker exposure to hazards is increased. 
There are many injuries associated with 
belt moves such as strains, sprains, lac- 
erations, etc. It is reasonable to ex- 
pect that a machine designed to perform 
the heavy portion of the task would re- 
duce the rate of these injuries. Addi- 
tionally, if the belt move shuts down 
production, the 3 to 8 h for a typical 
belt move becomes quite expensive. It 
is, therefore, also reasonable to expect 
that a machine designed to perform the 
heavy portion of the belt-move task could 
dramatically shorten the time required 
for the move. Significant cost savings 
could be realized through the use of this 
machine (5).^ 

•^Underlined numbers in parentheses re- 
fer to items in the list of references 
preceding the appendixes. 



The CBSM concept was conceived by the 
Bureau and was designed, fabricated, 
and demonstrated briefly by Tractor MBA 
(formerly MB Associates) in conjunction 
with West Virginia Armature Co. under Bu- 
reau contract J0333926 (2). 

The CBSM is a self-contained battery- 
powered vehicle capable of handling, 
storing, and transporting conveyor belt- 
ing, wire rope, and associated structures 
for sectional conveyor belts. The ma- 
chine has the potential to increase pro- 
ductivity and safety by reducing the 
heavy, arduous labor involved in typical 
belt moves. In testing, the CBSM was 
utilized for actual belt moves in mines 
of West Virginia and eastern Kentucky. 
The machine was used in a variety of con- 
ditions — thick and medium thick seams 
with both floor-mounted and roof-sup- 
ported belts, and in thin seams with 
floor-mounted belts. Although results 
using the CBSM for belt moves were prom- 
ising, changing conditions at the mines, 
e.g., new management, shutdown, etc., 
forced termination of the CBSM trials 
before a complete evaluation of the ma- 
chine could be made (1_, _3~4_, J3). 

Consequently, the Bureau entered into a 
cooperative agreement with United Coal 
Co. (UCC) for an extensive 3-yr in-mine 
trial and evaluation of the CBSM at the 
UCC Big First Mine in Kentucky. The coal 
seam at this mine pinched down to less 
than 48 in making the CBSM inoperable. 
As a result, this in-mine evaluation also 
had to be canceled prematurely. 

The CBSM was then brought to the Bu- 
reau's METF for an extensive surface test 
and evaluation program with the following 
objectives: 

1. Conduct testing to evaluate the 
CBSM capabilities and to determine if the 
CBSM functions per manufacturer's design. 

2. Conduct belt-move time trials on 
the CBSM to determine the reduction of 
labor and the time saved by using the 
CBSM. 



3. Improve machine reliability and 
performance. 

4. Prepare the CBSM for an extended 
in-mine trial. 

Surface testing of the CBSM at the 
METF commenced in August 1985. Final 



modifications to prepare the machine for 
in-mine trials were made in December 
1986. Results of the surafce test and 
evaluation program indicate that the CBSM 
has the potential to perform successfully 
in an underground mine in production 
mode. 



ACKNOWLEDGMENTS 



The authors want to extend their sin- 
cere appreciation to the following em- 
ployees of the Bureau's Pittsburgh (PA) 
Research Center for their contributions 
to this report: William D. Mayercheck, 
supervisory physical scientist, for tech- 
nical guidance of the research project 



from its inception; Robert J. Evans, 
civil engineer, for directions during 
surface testing. Additionally, the au- 
thors want to thank Stephen B. Nesbitt, 
mechanical engineer, Boeing Services In- 
ternational, for assisting in the test 
and evaluation of the CBSM. 



DESIGN CONCEPT 



In the conceptual design analysis, the 
Bureau identified the following compo- 
nents that should be featured on the 
machine: 

1. Batteries for power. 

2. Semiautomatic battery charger. 

3. Traction motors. 

4. Hydraulic system for operation of 
machine components. 

5. Belt handling mechanism. 

6. Wire rope handling mechanism. 

7. Large storage compartment for belt 
support structure. 

8. Compressed air supply for pneumatic 
handtools. 

9. Powered clamp hooks to connect the 
tailpiece to the service machine. 

The conceptual analysis also estab- 
lished the criteria that the machine 
should have complete mobility and be 
able to travel throughout the mine thus 



requiring four-wheel steering similar to 
a shuttle car. It was also determined 
that the machine should be able to tram 
in either direction from creep to up to 5 
mi/h. Drawbar capacity in the area of 
15,000 to 20,000 lb was also a desirable 
goal. 

In addition to the criteria established 
by the conceptual design, the following 
machine specifications were included in 
Tractor MBA's contract: 

1. The machine would be capable of a 
100-ft belt-move distance. 

2. The machine would be capable of 
operating in 48-in seams. 

3. The machine belt winder would ac- 
commodate belts up to 3/8 in thick by 42 
in wide. 

4. The machine belt storage capacity 
would be that amount which could be safe- 
ly and conveniently transported through 
the mine assuming 6-in top and bottom 
clearances. 

5. Battery meter. 

6. Fire extinguishing system. 



DESCRIPTION OF THE CBSM 



STRUCTURE 

The basic structure of the CBSM was 
chosen to be similar to that of a shut- 
tle car. The machine is 22 ft 11 in 
long and 10 ft 7 in wide with a ground 
clearance of 8 in. The overall height 
of the CBSM is 46 in. The CBSM has four- 
wheel steering on rubber-tired wheels. 
Figures 1, 2, and 3 are views of the 
machine. Appendix A lists the machine 
specifications. 

TRACTIVE SYSTEM 

A drawbar pull of 16,000 lb was se- 
lected for the CBSM based on an esti- 
mated weight of 32,000 lb for the fully- 
loaded machine, assuming a 50-pct grade 
ability factor. Two 30-hp, 1,750-r/min, 



120-V dc series motors were chosen as the 
drive motors. The motors drive the CBSM 
through a 1.668:1 traction drive gear 
box. The CBSM has a final overall gear 
reduction of 28.98:1. The machine is 
powered by two 32-cell storage batteries 
series connected rated at 128 V, 680 A/h. 
The motors are controlled by a silicon 
controlled rectifier, dc-to-dc chopper 
system manufactured by Siemens-Allis. 4 
This control system provides speed con- 
trol and dynamic braking. Figure 4 shows 
the electrical schematic for the CBSM. 
Figure 5 shows the operator tram control 
station. 

^Reference to specific products does 
not imply endorsement by the Bureau of 
Mines. 



Conveyor belt service 
machine 




FIGURE 1. -Conveyor belt service machine and associated belt-move equipment. 



Resistor box 



Auxiliary 
hydraulic ? r 
controls 

Air reservoir 



Double-tapped 
belt winder 




Control box 

Slat conveyor 

Wire rope 
winder 



>perator s 
■npartment 



FIGURE 2.-Conveyor belt service machine. 



Double - lapped belt winder 
Traction motors 



Wire rope winders 



Operator's compartment 







IOg 



FIGURE 3.-Conveyor belt service machine layout. 




0) 

.Q 



o 
>. 

0) 

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c 
o 
U 
I 



UJ 



o 



■Hi-, 



jlsJLf. Lfifij 




— o 



- E 

a 

5 E 

is 

i. 




FIGURE 5.-Operator tram control station. 



HYDRAULIC SYSTEM 

One hydraulic pump powers all of the 
machine's functions with the exception of 
the wheel drive. The pump is rated at 20 
gal/min at 1,500 psi and is driven by a 
20-hp, 1,800-r/min, 120-V dc motor. The 
capacity of the hydraulic reservoir is 
18.7 gal. Hydraulic motors power the air 
compressor, belt reel, slat conveyor, and 
the wire rope reels. The steering has 
hydraulic assist. Hydraulic cylinders 
activate the grab hooks and locking pins 
and raise and lower the slat conveyor. 
Figure 6 shows the hydraulic schematic 
for the CBSM. Figure 7 shows the hydrau- 
lic control station. 



Service brake 



42000 



*) " < mf 



4Q 



% 



"00- 



<> 



Parking brake 







Hydraulic take off 

143' 



fa 




L. 



Impact wrenches Chipper Splice 
pin tool 



35 



-] | Slat conveyor 



I ,V~ " @ 2200 ^fc^lAtU f^ I 

-^^ lb i3» i *HSL ^ I ' : I^V^ 
)pe winders w Belt winders ' ♦ ' 




Notes: 
I. All components are as shown or equivalent 

2 Typical pressure adjust to suit conditions. 
3. Item 31 selector valves: 

position- I. High pressure (maximum tension) 

2. Off 

3. Reduced pressure (constant winding tension.) 



FIGURE 6.-Conveyor belt service machine hydraulic schematic. 




FIGURE 7.-Hydraulic control station. 



Belt drum 
end plate 



Belt drum 
mounting frame 




Hydraulic motor 



Belt hook 
tube 

Belt 



Chain coupling 




elt hook 
clamp 



FIGURE 8.-Belt reel drive mechanism. 



BELT WINDING SYSTEM 

The belt winder on the CBSM double 
winds the belt onto the reel. The belt 
winder is composed of two reels, the wire 
rope lead reel and the main reel. The 
winder has a primary 
motor rated at 50 r/min 
tension of 1,400 lb at 
winder has a secondary 
motor rated at 50 r/min 
tension of 2,000 lb at 



drive hydraulic 
with a maximum 

1,500 psi. The 
drive hydraulic 
with a maximum 
1,500 psi. To 
wind a belt on the reel, a belt hook tube 
that is connected to the wire ropes on 
the lead reel is paid out from the CBSM. 
The tube is placed inside the belt at the 
midcenter of the belt section that is to 
be wound and is clamped in place. The 
wire rope lead reel is then actuated to 
begin reeling in the wire ropes and the 
belt attached to them. The lead reel 
pulls the belt through the machine into 
the center of the main reel. When the 
belt is in place, the torque is trans- 
ferred to the rotation of the main reel. 
As the main reel rotates, the belt is 
wound on the reel. As the belt is wound 
on the reel and greater torque is re- 
quired to continue winding the belt under 
tension, the secondary drive hydraulic 
motor is activated. Figure 8 shows 
the belt reel drive mechanism. Figure 9 
shows the belt reel. 

The belt storage capacity is that quan- 
tity of belt that can be stored on a 
12-in-diameter roll plus the 30 ft that 
is stored in the machine under the slat 





\Belt 




FIGURE 9.-Belt reel. 



conveyor. The belt storage length capac- 
ity varies with both roll diameter and 
belt thickness. The size of belt roll 
that can be safely and conveniently 
transported through the mine is limited 
by floor and roof clearance. In seams 
under 52 in, the maximum size roll would 
have its center midway between the mine 
roof and floor. The belt roll center 
height is adjustable for the purpose of 
maximizing storage capacity. Assuming 
that 6-in top and bottom clearance is 
adequate for transporting a belt roll, 
the maximum belting that can be carried 
would be equal to the seam height minus 
12 in. In seams over 52 in, the storage 
capacity is established by frame clear- 
ance limits that allow a roll diameter of 
40 in. Figure 10 is a graph of the belt 
storage capacity in feet as a function of 
belt thickness and outside diameter of 
the roll. 

WIRE ROPE HANDLING SYSTEM 

The wire rope handling system is com- 
posed of two reels, one on each side of 
the CBSM (fig. 11). Each reel is driven 
by a hydraulic motor rated at 60 r/min 
with a maximum tension of 6,000 lb. The 
motors operate through 31:1 gear re- 
ducers. There is more than sufficient 
torque available for tensioning the wire 
ropes. Each motor is separately con- 
trolled by a pair of lever handle valves. 
One is an on-off valve and the other is 
for the selection of either a high or low 
preselected pressure. 

PNEUMATIC SYSTEM 

The pneumatic system supplies com- 
pressed air for hand-held air tools. The 
two-stage compressor is hydraulically 
driven and rated at 5 hp , 20 ft 3 /min at 
100 psi (fig. 12). The air receiver tank 
has a capacity of 7.5 gal. The air pres- 
sure is maintained between 80 to 100 psi 
by the combination of an electric pres- 
sure switch and a normally open hydraulic 
on-off solenoid valve. There are female 
quick-coupled air connectors at each cor- 
ner of the vehicle. 



10 



01 c 

LU -E 

\- ~ 

LU -I 

1^ 

5 K 

Q UJ 

I- u- 

Z> o 
O 



44 



40- 



36 



32 



28- 



24 
80 



Belt thickness, in 

0.50- 




^230 ft, max for 
42-in seam 



j. 



140 160 180 200 220 240 260 

SERVICE MACHINE BELT CAPACITY, ft 

FIGURE 10. -Service machine belt storage capacity. 



280 300 




FIGURE 11. -Left wire rope reel. 



WORK PLATFORM 

For the CBSM to perform as designated, 
it is necessary to have a work platform 
or worktable to hold the return belt off 
the ground and the feed belt apart from 
the return belt and above the worktable 's 
platform or shelf. This shelf provides a 
means of sliding the troughing rollers 
across under the feed belt. With the re- 
turn belt held off the ground, the wire 
rope support structure with the return 
idler can then be easily slid under the 
return belt. 

In order to demonstrate the CBSM in an 
aboveground belt move, it was necessary 
to construct a tailpiece to be used for 
the demonstration. The original design 
of the work platform required that it be 
welded to the outby end of the tailpiece. 
The work platform presently being used 
with the CBSM is of a later design and 
does not require welding to the tail- 
piece. It is a free standing assembly 



11 




FIGURE 12.-Air compressor. 



that is secured to the tailpiece with 
chains during a belt move. Figure 13 
shows the work platform. 



the possible use of a bridge for roof 
supported structures rather than the work 
table for roller installation.) 



BELT-MOVE EXTENSION PROCEDURE 

Figure 14 is a visualization of the 
intended use of the CBSM and accessories 
during a belt-move extension procedure in 
a low-seam-height mine entry. Figure 15 
shows the CBSM hooked into the tailpiece 
hitch. 

The following outlines the proposed 
belt-move extension procedure on a floor- 
supported belt system using the CBSM. 
(The roof-supported conveyor belt exten- 
sion procedure is identical except for 



o Position belt splice at inby end of 
tailpiece. 

o Detach conveyor system wire rope and 
tailpiece anchors. 

o Push tailpiece with CBSM toward belt 
drive to obtain slack in belt. 

o Attach conveyor system wire rope on 
CBSM. 

o Attach worktable to tailpiece. 



12 



12" 



t 



12" 



I 



8 i 



33" 18" i 



I" 



in 



18' 



33 



T 



5p 



tz 



□ 



._! 



Li 



■CD 



3 2" 



,'■1 I. 



22' 



^ 



55' 



M 



Ell 



F rd 



1-1 



l> 



HQ 



OH 



t 
i i 

!~- 1 

2 
M — l 

n 
ft! 



It 



M 



i 



Ji i 



FIGURE 13.-Work platform. 



o Disconnect splice at tailpiece and 
connect conveyor belt to belt on CBSM. 

o Connect and lock tailpiece to CBSM. 

o Install rollers while moving tail- 
piece and worktable with CBSM inby until 
belt clamp has been dispensed from CBSM. 

o Remove worktable and unhook belt 
clamp. 

o Pull tailpiece with CBSM until con- 
veyor belt is fully extended. 

o Assure that center of belt conforms 
to entryway markers. 

o Dismantle worktable. 

o Pull wire rope tight using CBSM 
winches. 



o Anchor wire rope and tailpiece to 
floor. 

NOTE: The steps or previous assump- 
tions may be modified to achieve the min- 
imum amount of time and labor necessary 
to complete the procedure. 

BELT-MOVE RETRACTION PROCEDURE 

The following steps outline the pro- 
posed belt move retraction procedure for 
a floor-supported conveyor belt system 
using the CBSM. (The roof-supported re- 
traction is similar. ) 

NOTE: The worktable is not used during 
the retraction belt move sequence, 

o Position splice connectors on con- 
veyor to where the midpoint of the belt 
to be removed is at tailpiece roller. 



13 



Belt storage reel CBSM 



Conveyor belt 

Top rollers 




y^e^a^ 



FIGURE 14.-Extension procedure. 




FIGURE 15.-Tailpiece hitch. 



o Detach conveyor system wire rope and 
tailpiece anchors. 

o Push tailpiece with CBSM toward 
drive to obtain slack in belt. 

o Hook belt clamp to belt and wire 
rope to CBSM winches. 

o Connect and lock tailpiece to CBSM. 

o While pushing the tailpiece, load 
the CBSM with belting, wire rope, and 
rollers. 

o When the splice is positioned be- 
tween the tailpiece and CBSM, detach 
tailpiece from CBSM. 

o Disconnect and load the retracted 
conveyor belt and reconnect conveyor belt 
splice. 

o Pull tailpiece with CBSM until con- 
veyor belt is fully extended. 



14 



o Assure the center of belt conforms 
to entry way markers. 

o Pull wire rope tight using CBSM 
winches. 

o Anchor wire rope and tailpiece to 
floor. 

NOTE: The steps or previous assump- 
tions may be modified to achieve the min- 
imum amount of time and labor necessary 
to complete the procedure. 

INITIAL ABOVEGROUND AND UNDERGROUND 
TESTING AND MODIFICATIONS 

Prior to bringing the CBSM to the METF, 
the machine did receive some aboveground 
and underground testing. The initial 
aboveground tests were performed at the 
West Virginia Armature New River manu- 
facturing plant. A belt extension and 
retraction was simulated using conveyor 
belting, wire rope, and belt support 
structures. As a result of these initial 
aboveground tests, a number of modifica- 
tions were made to the machine. The 
hydraulic pump was changed to increase 
power. The control valve system for the 
hydraulic hose circuits were revised to 
reduce back pressure in the return lines. 
The work platform was redesigned to be 
easily movable from one tail section to 
another. The belt winder was rebuilt to 
improve its wind-up capabilities. 

The first underground demonstration of 
the CBSM took place at the ARMCO Robin 
Hood Division, No. 9 Mine, West Virginia. 
The machine was used for only one belt 
move in this mine, but it performed ex- 
ceptionally well. The belt move was a 
160-ft conveyor belt retraction. The ma- 
chine was used to wind up 320-ft of 1/4- 
by 36-in conveyor belting. The CBSM was 
used to transport this belting along with 
the belt's structural supports, wire 
rope, sail anchors, and auxiliary mate- 
rial to the storage area, two sections 
further in the mine. 

New management at this mine could not 
accommodate continued testing of the 
CBSM, so it was moved to ARMCO 's Big 
Mountain Coal Co. mine. Prior to use in 
this mine, the lead wire rope follower on 



the CBSM was redesigned to improve its 
function of preventing wire cross-over or 
overlapping on the sheave. 

The CBSM was used to assist in two belt 
moves at the Big Mountain Coal Co. mine. 
In the first move, the machine was used 
to load belting to be used in the belt 
extension and to move the tailpiece and 
lay out the belt. During the move, the 
CBSM had trouble moving through a bad 
section of floor. Overloads on the trac- 
tion motors caused the 400-A main fuse to 
blow. However, after filling the hole in 
the bad section of floor with timbers and 
replacing the fuse, the CBSM was able to 
complete its task. 

The second belt move at the Big Moun- 
tain Coal Co. mine was unsuccessful. The 
CBSM could not start because of an elec- 
trical fault. Additionally, a steering 
drag link had broken and a steering link- 
age pin had sheared. The CBSM, there- 
fore, had to be removed from the mine so 
that proper repairs could be made. 

As a result of these failures, the 
steering linkage pins were redesigned to 
provide greater strength and the drag 
lines were rebuilt. Also during this 
period, hitch adaptors (fig. 16) were de- 
signed and fabricated to improve the per- 
formance of the hitches when pushing 
against the tail section when moving the 
tail section outby. At this time, the 
400-A main fuses were replaced by a cir- 
cuit breaker. 

While these modifications were being 
made to the CBSM, production was sus- 
pended at the Big Mountain Coal Co. mine. 
The CBSM was then taken to a UCC contract 
mine in Kentucky. To provide conclusive 
testing, the Bureau entered into a co- 
operative agreement with UCC for a 3-yr 
in-mine evaluation program for the CBSM 
at UCC's Big Fist Mine. At this mine, a 
series of five belt extensions were con- 
ducted using the CBSM. The machine per- 
formed well during these belt extensions 
with no major mechanical failures. Each 
move was made using a new inexperienced 
crew. Even so, the total time required 
for the belt extensions was reduced from 
4 h for the first extension to 3 h for 
the fifth extension. All belt extensions 
were 120 ft. The time to install the 
belt structures was only 15 min on the 



15 




Tailpiece hitch 
adapter 





HI 







FIGURE 16.-Tailpiece hitch adaptors. 



fifth extension. However, when the coal 
seam at this mine pinched down top less 
than 48 in, the CBSM became inoperable. 
Therefore, the agreement was cancelled 



and the CBSM was brought to the METF for 
extensive surface testing and evaluation 
prior to any additional in-mine trials. 



SURFACE TESTING 



TEST PROGRAM OVERVIEW 



The original intent of the surface tri- 
als at the METF was to conduct capability 
tests and make 120-ft belt moves by the 
CBSM under simulated underground coal 
mine conditions. Extension and retrac- 
tion belt move tests were to be conducted 
simulating moves for both floor and roof- 
supported conveyor belt haulage systems 
in areas representing both low and high 
coal seams. A determination was to be 
made as to the reduction of labor and 
time that could be saved through the use 
of CBSM for belt moves. However, a prob- 
lem that developed early in the surface 



test program necessitated that the test 
program be altered drastically. 

On December 9, 1985, while undergoing 
battery capability testing, the left 
traction motor failed. Subsequent inves- 
tigation of the failure led to the con- 
clusion that this traction motor would 
have to be replaced. Unfortunately, a 
replacement motor was not received un- 
til July 16, 1986, and the installation 
was not completed until August 4, 1986. 
Additionally, after reinstalling the tram 
motor, during machine checkout, the CBSM 
hydraulic pump failed on August 26, 1986 
and a replacement could not be installed 
until Septaeraber 4, 1986. Consequently, 



16 



approximately 9 months was lost from the 
test program because of the failure of 
these two components. During this 9- 
month period, minor machine refurbish- 
ment was proceeding but preparations for 
belt move testing were placed on hold. 
The test program was impacted further by 
the requirement that surface testing on 
the CBSM be completed by October 3, 1986. 
In view of the fact that less than 1 
month remained in which to do any surface 
testing on the CBSM and that it would be 
impossible to complete preparations for 
simulated belt moves in that time, the 
decision was made to eliminate belt moves 
from the surface test program. The test 
program would, therefore, concentrate 
solely on CBSM system capability testing 
and preparations for in-mine testing of 
the CBSM. 

Surface tests were conducted to verify 
and measure the performance of the CBSM. 
Battery drawdown tests were conducted. 
Heat stabilization for the hydraulic sys- 
tem was checked. Tram speed, braking, 
and duty cycle were measured. The per- 
formance of the belt winder system was 
also investigated. Numerous modifica- 
tions were made to the CBSM to correct 
deficiencies noted during surface test- 
ing. A description of each test sequence 
follows. 

BATTERY CAPABILITY TEST 

Battery capability trials were per- 
formed with the objective to determine 
the batteries capability in providing the 
necessary power to conduct all required 
belt move procedures. The tests were 
conducted to determine the time required 
to discharge the batteries to 80 pet of 
full charge under idling and tramming 
conditions. 

The battery voltage was recorded on a 
Racal store 14 FM tape recorder. The 
battery level meter was removed and the 
voltage monitored at that point. The 
data tapes were played back on a Nicolett 
3091 digital storage scope interfaced to 
a Hewlett-Packard 9845B desk top computer 
to produce a printout of the battery 
voltage versus time. 



A test, monitoring the battery voltage 
while the hydraulic drive motor and 
lights were energized, showed no appreci- 
able voltage drop. In order to simulate 
a realistic load on the batteries, the 
CBSM was cribbed up and the traction 
motors activated to increase the load. 
The batteries were fully charged. For 
the first few minutes of each test, only 
the hydraulic drive motor (120 V dc, 20 
hp) and the machine lights were energized 
to load the system. At this point, the 
two traction drive motors (120 V dc, 30 
hp each) were then energized. The time 
was then measured to reach the 80-pct- 
drawdown level for the batteries. 

During the first test, the battery 80- 
pct-drawdown point was reached at the 
64-min mark. For this test the batteries 
had only been charged for 3.5 h prior to 
the test. The batteries were charged for 
8 h prior to the remaining tests. The 
results of the remaining tests indicated 
that the batteries did not receive a suf- 
ficient charge after 3.5 h but that an 
8-h charge was of sufficient length to 
return the batteries to their full 
potential. 

The three remaining tests were all 
stopped before the 80-pct battery level 
was reached because of a variety of rea- 
sons. The second test was stopped be- 
cause of conflicts with other project 
testing being performed in the same area 
as the CBSM testing. The third and 
fourth tests were stopped when a battery 
cable failed and when a traction motor 
failed. Although the last three battery 
tests were all terminated before the 80- 
pct level was reached, the testing did 
not indicate any shortcomings in the bat- 
tery power system on the machine. During 
the third test, the CBSM ran for 115 min 
with the batteries dropping only to the 
86-pct level. This would seem to indi- 
cate that, on a full 8-h charge, suffi- 
cient power exists to perform all of the 
required belt move procedures. The prob- 
lems that occurred during the third and 
fourth tests were corrected and are con- 
sidered to be isolated problems that 
should not reoccur. Figure 17 shows the 
results of the four battery tests. 



17 




u 


40 


> 




LU 


20 


O 




< 




h 





_l 




o 




> 


140 


> 




DC 




UJ 


120 


r- 




r- 




< 

m 


100 



J L 






20 40 60 80 100 120 140 20 40 60 80 100 120 140 

TIME.min 

FIGURE 17.-Conveyor belt service machine battery capability tests. A, Test 1;B, test 2; C, test 3; D, test 4. 



HYDRAULIC SYSTEM HEAT 
STABILIZATION INVESTIGATION 

The objective of the heat stabilization 
tests was to determine if the operating 
temperature of the CBSM hydraulic system 
would stabilize at a safe level. The 
CBSM hydraulic system uses a variable 
displacement pressure compensated piston 
pump. The control valves are closed cen- 
ter. There is a solenoid-operated two- 
way bypass valve for use during startup 



of the pump motor to unload the pump dur- 
ing startup to allow the pump to prime. 
The pump is a piston type with a maximum 
output of 20-gal/min. The hydraulic tank 
capacity is approximately 18.7 gal. Fig- 
ure 18 shows the pump and reservoir. 

To perform the test, a Hedland 2 to 30 
gal/min flowmeter was installed in the 
pump output line. A 3,000-psi pressure 
gage was installed to monitor the pump 
output pressure. A type K thermocouple 
was placed in the hydraulic tank through 



18 




FIGURE 18. -Hydraulic pump and reservoir. 



a breather in the top of the tank. 
Another type K thermocouple was used to 
measure ambient temperature. Two tests 
were run. Test 1 was run under no-load 
conditions with no hydraulic circuit be- 
ing operated. Test 2 was run with the 
right-hand wire rope circuit operating 
under very light load. The cable was not 
anchored and, therefore, rotated freely. 
Table 1 is a tabulation of the test 
measurements. 

For test 1, after approximately 36 min, 
the system reached 207° F. The test was 
terminated at this point because of the 
high temperature. The temperature rise 
was 139°. The oil temperature in the 
tank reached a final temperature of 137° 
above ambient. The tank was not even 
near stabilization temperature; the rate 
of rise was 22° per 5 min. Operating 
pressure of the system was 2,000 psi at a 
flow rate of 3 gal/min. 



For test 2, when operating the winch 
system (under no load), the flow rate was 
10 to 11 gal/min and operating pressure 
was 325 psi. After 1 h 20 min the tank 
temperature reached 186° F or 112° above 
ambient. Tank temperature rose 103° dur- 
ing this period. The system was nearing 
stabilization; temperature rise was 2° 
per 5 min. 

Although 186° F may be an acceptable 
temperature, it is not known how hot the 
system may get under actual operation. 
If the temperature had stabilized at a 
somewhat lower temperature, it would be 
expected that the system would operate 
at a safe temperature as long as one or 
more circuits were operating. For this 
reason, the tank temperature was moni- 
tored during the test program in order 
to ascertain if a problem exists during 
normal system operation. During tram 
duty cycle testing, the maximum oil 



19 



TABLE 1. - CBSM hydraulic heat stabilization test results 



Elapsed 


System 
pressure, psi 


System flow, 
gal/min 


Temperature, °F 


time, min 


Oil Ambient Difference 



HYDRAULIC SYSTEM IDLING, NO FUNCTIONS OPERATING 



0., 
10. 
15. 
20. 
25. 
30. 
35. 
36. 




2,000 
2,000 
2,000 
2,000 
2,000 
2,000 
2,000 



67.8 
67.9 
92.0 
136.2 
157.8 
180.1 
202.0 
207.0 



69.0 
68.7 
69.2 
69.5 
69.8 
69.8 
69.6 
69.8 



-1.2 

-.8 

22.8 

66.7 

88.0 

110.3 

132.4 

137.2 





OPERATING 


WINCH SYSTEM UNDER NO 


LOAD 






325 


10.0 


82.8 


71.9 


10.9 


3 


325 


10.0 


84.5 


72.1 


12.4 




325 


9.5 


94.5 


72.4 


22.1 


13 


325 


9.5 


104.1 


72.2 


31.9 


18 


325 


10.0 


114.0 


72.6 


41.4 


23 


325 


11.0 


124.1 


72.6 


51.5 


28 


325 


11.0 


133.4 


72.8 


60.6 




325 


11.0 


142.9 


72.7 


70.2 




325 


11.0 


150.3 


72.4 


77.9 




325 


11.0 


156.5 


72.4 


84.1 


48 


325 


11.0 


162.9 


72.3 


90.6 


53 


325 


11.0 


168.0 


72.7 


95.3 


58 


325 


11.0 


172.3 


73.0 


99.3 




325 


11.0 


176.6 


72.2 


104.4 


68 


325 


10.0 


180.6 


73.3 


107.3 




325 


10.5 


183.6 


75.0 


108.6 




325 


10.5 


185.5 


74.0 


111.5 










185.6 


73.9 


111.7 



temperature noted was 149° F. This would 
seem to indicate that the hydraulic sys- 
tem on the CBSM is stable from a thermal 
standpoint to operate successfully under- 
ground. Figure 19 gives plots of temper- 
ature versus time for these tests. 

SPEED TESTS 

The objective of the CBSM speed test 
was to determine the ground speed of the 
CBSM. The CBSM was designed for a ground 
speed of 4 mi/h. A 100-ft section of a 
straight, level, and paved roadway was 
marked off. An observer was stationed at 
the end. The elapsed time the CBSM took 
to cover the 100-ft course was recorded 
with a stopwatch. Three runs were made 



in forward direction and three in the re- 
verse direction. The average speed for 
these six runs was 7.6 ft/s or 5.2 mi/h. 
The batteries were charged to approxi- 
mately 120 V, 94 pet of full charge at 
the start of the runs and approximately 
117 V, 91 pet at the end of the runs. 

The speed of the CBSM was also checked 
with the CBSM climbing up a paved roadway 
with an approximate grade of 17 pet. An 
observer used a stopwatch to measure the 
time it took the CBSM to traverse a 50-ft 
section of the roadway. Three runs were 
made. Average speed up the grade was 3.7 
ft/s or 2.5 mi/h. These runs began with 
the batteries at the 117-V mark and con- 
cluded the three runs at approximately 
113 V or 88 pet. 



20 



Ll 

o 

UJ 
QT 

3 
I- 
< 

a: 

UJ 

CL 

UJ 

I- 




g< 1 ■ 1 ■ 1 - 


...... 


• 


_ • 


• 


- • - 


• 


-• _ 


'.I.I.I. 



10 



20 30 20 

TIME, min 



40 



60 



80 



FIGURE 19. -Heat stabilization test. A, No-load operation; B, winch circuit actuated. 



One run was repeated for the level road 
section after the batteries had been 
fully charged. On the level section, the 
CBSM averaged 7.9 ft/s or 5.4 mi/h. Ta- 
ble 2 tabulates the results of the speed 
tests. The speed tests verify that the 
CBSM has acceptable speed on adequately 
charged batteries. 

TABLE 2. - CBSM speed test results 



Trial 



Direction 



Elapsed 
t ime , s 



Battery 
charge, V dc 



100-ft, LEVEL, PAVED ROADWAY; 
AV TRAM SPEED — 5.2 mi/h 



1 


Forward. . 


12.86 


120 


2 


. . .do. ... 


11.99 


NM 


3 


• • .do • • • • 


12.21 


NM 


4 


Reverse. . 


14.43 


NM 


5 


. . .do. ... 


14.13 


NM 


6 


• . .do. ... 


13.74 


117 



50-ft, 17-pct 
AV TRAM 



GRADE, PAVED ROADWAY, 
SPEED--2.5 mi/h 



7 

8. • • • • 

y o • • • • 


Forward. . 
• . .do. . . . 
. . .do. ... 


13.49 
13.95 
13.61 


117 

NM 

113 


100-ft LEVEL, PAVED ROADWAY, FULL 
BATTERY CHARGE; TRAM SPEED— 5.4 mi/h 


10 

11 


Forward. . 
Reverse. . 


12.28 
13.11 


128 
128 


NM Not 


measured. 







BRAKING TESTS 

The objective of the braking tests was 
to measure the braking capability of 
the CBSM. The tests were performed on 
a flat, paved roadway. The CBSM was 
trammed to full speed, 7.9 ft/s. At a 
predetermined point, the brakes were ap- 
plied. The stopping distance of the ma- 
chine was then measured. Three runs were 
made in the forward direction and three 
in the reverse direction. Stopping dis- 
tances were measured when only the ser- 
vice brakes were used and then when only 
the parking brakes were used. Using only 
the service brakes, the average stopping 
distance for the CBSM was 49.5 in or 4.1 
ft. Repeating the procedure, using only 
the parking brake, gave an average stop- 
ping distance of 69.3 in or 5.8 ft. 

The braking system of the CBSM was also 
checked while the machine was descending 
a paved roadway with an approximate grade 
of 21 pet. The actual stopping distance 
was not measured. However, applying both 
service and parking brakes simultaneously 
locked all four wheels. Results of the 
braking test indicate that the CBSM brak- 
ing system performs in a satisfactory 
manner for in-mine use. Table 3 lists 
the results of braking tests. 



21 



CURRENT DRAW TEST 

The objective of the current draw test 
was to measure the current draw on the 
electrical system as a variety of hydrau- 
lic loads were actuated on the CBSM. The 
current was measured at the 175-A fuse 
in the hydraulic pump control box. The 
current was measured with a clamp-on 
ammeter, Amprobe model ACDC 1000. Flow 
rate was measured with a Hedland 2 to 
30 gal/min flowmeter installed in the 

TABLE 3. - CBSM braking test results 



Trial 



Direction 



Stopping 
distance, in 



LEVEL, PAVED ROADWAY, SERVICE BRAKES; 
AV STOPPING DISTANCE— 49.5 in 



1 




62 






46 






58 


4 




42 






47 


6 




42 



LEVEL, PAVED ROADWAY, PARKING BRAKES; 
AV STOPPING DISTANCE— 69.3 in 



7 




71 






88 






71 


10 




61 






67 






58 



pump output line. Pressure was measured 
with the 3,000-psi pressure gage mounted 
on the machine. Batteries were fully 
charged. Voltage was measured across the 
positive and negative terminals in the 
hydraulic control case. 

Table 4 tabulates the results of the 
current draw test. As can be seen from 
the results, the current draw of the hy- 
draulic pump motor varied from a low of 
44 A with no loads operating to a high of 
129 A with the compressor being driven. 
The results of the test indicate that the 
measured current for the functions actu- 
ated were within reasonable limits and 
would pose no problems for the electrical 
system on the CBSM. 

CONTROLLED TENSION TESTS 

The objective of the controlled tension 
test was to measure the belt tension as 
it unwinds off the belt winder reel. In 
a belt move, controlled tension on the 
belt when it is being extended is desir- 
able. When using the worktable to hold 
the return belt off the ground and the 
feed belt apart from the return belt, 
some tension on the belt will permit it 
to slide off the worktable and not crash 
to the floor. This would greatly facili- 
tate setting the troughing idlers under 
the top belt. 



TABLE 4. 



CBSM current draw test results 



Test 


Condition 


Flow 
rate, 
gal/min 


System 

pressure, 

psi 


Current , 
A 


Voltage, 
V dc 


1 


Belt winder off, winder assist 
on; high pressure. 

No circuits actuated, hydraulic 
pump running. 

Belt winder on; dual motor on; 
high pressure. 

Compressor on; all other cir- 
cuits off. 

Belt winder on, high pressure; 
assist on tramming forward to 
reel belt in. 


12 
22 
<2 
11 

NAp 


450 
2,000 
2,000 
1,550 

NAp 


65 

44 

46 

129 

x 60- 80 


132 


2 


133 


3 

4 

5 


133 
128 

NAp 





NAp Not applicable. i Hydraulic motor current. 



22 



The design of the belt winder hydraulic 
system is such that a number of modes can 
be employed in the operation of the belt 
winder reel. The hydraulic drive system 
includes two hydraulic motors and two 
pressure regulating valves. One regulat- 
ing valve, the low-pressure valve, is ad- 
justable to 500 psi. The other regulat- 
ing valve, the high-pressure valve, is 
adjustable to 2,200 psi. Through the use 
of control valves in the system, it is 
possible to operate with either single or 
dual motors in either low or high pres- 
sure. The assumptions made in the design 
of the system are that belt winder would 
normally be operated with a single motor 
in low-pressure mode. If torque is in- 
sufficient, then the second motor would 
be actuated. If still more torque is re- 
quired, then the pressure setting would 
be switched to the high settting. 

To measure the belt tension, the belt 
was attached to a Dillon 10,000-lb dyna- 
mometer was anchored to columns in the 
miner-bolter test structure. Pressure 

TABLE 5. - Belt winder controlled 
tension test results 

(Drum diameter — 34 in start, 
28 in final) 



Test 


Circuit 
pressure, psi 


Belt tension, 10 3 lb 




Start 


Final 


SINGLE MOTOR, LOW PRESSURE 


1... 
2... 
3... 


1,800-1,850 
1,800-1,850 
1,750-1,850 


0.4 
.4 
.4 


0.7 -0.9 
.7 - .9 
.7 - .9 


SINGLE MOTOR, HIGH PRESSURE 


4... 
5... 
6... 


2,000-2,050 
2,000-2,050 
2,000-2,050 


0.7 -0.8 
.65- .8 
.65- .75 


0.75-1.15 
.8 -1.15 
.7 -1.0 


DUAL MOTORS, LOW PRESSURE 


7... 
8... 
9... 


1,800-1,850 
1,800-1,850 
1,800-1,850 


0.7 -0.8 
.7 - .8 
.7 - .8 


1.1 -1.6 
1.4 -1.8 
1.4 -1.8 


DUAL MOTORS, HIGH PRESSURE 


10.. 
11.. 
12.. 


2,000-2,050 
2,000-2,050 
2,000-2,050 


1.0 -1.1 

.9 -1.1 

1.0 -1.1 


1.7 -2.1 

1.7 -2.05 

1.8 -2.2 


BELT WINDER FREE WHEELING 


13.. 
14.. 
15.. 







NM 
NM 

NM 


0.35-0.5 
.2 - .375 
.35- .45 



NM Not measured. 



was measured on the machine-mounted pres- 
sure gage. The test was performed by 
tramming the CBSM backwards to unwind the 
belt. Belt tension was then read direct- 
ly from the dynamometer. A number of 
different test conditions were investi- 
gated — single motor, low and high pres- 
sure; dual motors, low and high pressure; 
free wheeling, etc. Table 5 lists the 
results of the controlled tension tests. 
Results of the tests indicate that the 
design of the CBSM is such that adequate 
tension can be maintained while extending 
the belt. Based on the hydraulic config- 
uration used, it is possible to select a 
range of tension for a given situation. 

STATIC PULL TEST 

The objective of the static pull test 
was to determine the tension that belt 
winder system would apply to the belt in 
a static mode, i.e., with the CBSM sta- 
tionary. As in the controlled tension 
test, a number of test conditions were 
investigated — single motor, low and high 
pressure; and dual motors, low and high 
pressure. As with the controlled tension 
test, tension was measured using a Dillon 
10,000-lb dynamometer anchored to col- 
umns in the miner-bolter test structure. 
Pressure was measured on the machine- 
mounted pressure gage. 

The test was performed with the CBSM 
stationary. The belt winder motors were 
then actuated to see what tension could 
be applied to the belt. Table 6 lists 
the results of the test. A low-pressure 
setting of 350 psi was not sufficient to 
begin reeling in the belt regardless of 
whether the single or dual motor set up 
was used. Only in the high-pressure set- 
ting, the belt winder was capable of 
winding and maintaining tension on the 
belt. A check was not made to see if the 
low-pressure setting could be raised to a 
setting that would be sufficient to begin 
reeling in the belt as designed. 

TRAM CURRENT TEST 

The objective of the tram current test 
was to measure the current draw as the 
machine was trammed. The CBSM traction 
system is powered by two 30-hp motors 



23 



TABLE 6. - Belt winder static pull 
test results 

(Belt diameter — 28 in) 



Test 


Circuit 
pressure, psi 


Belt 
tension, lb 


SINGLE MOTOR, LOW PRESSURE 


1 


350 
350 
350 




l 


2 


1 




l 


SINGLE MOTOR, HIGH PRESSURE 


4 


2,050 
2,050 
2,050 




275 


5 


450 




400 


DUAL MOTORS, LOW PRESSURE 


7 


350 
350 
350 




1 


8 


l 




*0 


DUAL MOTORS, HIGH PRESSURE 


10 

11 


2,050 
2,050 
2,050 




650 
725 


12 


675 



Unable to move belt. 

rated at 120 V dc, 212-A full-load cur- 
rent. A clamp-on ammeter, Amprobe model 
ACDC 1000, was used to measure current. 
The CBSM was trammed over a level paved 
roadway and up with a grade varying be- 
tween 17 to 21 pet. During tramming, the 
CBSM hydraulic pump motor was also ener- 
gized. The current draw of the hydraulic 
pump motor was measured at 44.4 A. While 
tramming on the level surface, the CBSM 
drew 275 A total or 230.6 A for the tram 
motors. Battery voltage was measured at 
119 V. While tramming up the grade, the 
CBSM drew considerably more current. 
Full-load current was measured at 530 A 
of 485.6 A for the tram motors. Battery 
voltage while tramming up the grade was 
107 V. Table 7 lists the results of the 



tram current test. The test indicates 
that the electrical system and traction 
drive system will perform satisfactorily 
in mine roadways varying in gradient up 
to 17 pet. In the tram conditions inves- 
tigated, the current measured are within 
the rated capacity of the batteries. 

TRAM DUTY CYCLE TEST 

The objective of the tram duty cycle 
test was to determine the tram duty cycle 
of the CBSM. To perform this test, a 
2,829-ft (fig. 20) course was laid out 
on a paved roadway. This course included 
a 206-ft section of roadway with a 17-pct 
grade. The test involved tramming the 
CBSM over this course until the batteries 
dropped to a level low enough to prevent 
continued tramming. During the test, 
battery voltage and current draw were 
measured. Hydraulic oil temperature was 
also monitored. The air compressor was 
disabled for the test to reduce the loads 
on the system to just the traction motors 
and the hydraulic pump motor. 

Over the course of one 8-h shift, the 
CBSM completed 10 circuits of the course 
before the batteries fell to a level low 
enough to stop tramming. Weather, lunch 
breaks, and other traffic prevented the 
duty cycle test from being performed 
without interruption. Batteries were not 
recharged during the shift. The CBSM 
covered a distance of 5.4 miles on one 
battery charge. Only one anomaly showed 
up during the test. Prior to the test, 
the CBSM was trammed up the slope on the 
course in forward and reverse to detect 
any differences in performance. The ma- 
chine would not tram up the grade in re- 
verse. The instantaneous overloads would 
trip. There was no apparent reason for 



TABLE 7. - Tram current test results 



Test 


Condition 


Battery 


Total 






voltage, V dc 


current, A 


NAp .... 
2 




135.7 
131.6 
119.0 


NAp 
44.4 
250-300 


Hydraulic pump on; no load... 
Tram in reverse on level, 


3 


paved roadway. 
Tram up paved roadway; 
17- to 21-pct grade. 


106.0-108.0 


510-550 



NAp Not applicable. 



24 



Parking area 



Building : 

54 i 




y / , , s , , / s / s,A 



/ * f f / i t t f t } t } r f / » > r 



I Building 155 



'■'''J.'ss'S 



Building 152 



//s,,;s*ss,,,s;ssss/ s s, 




Finish, 
2,829 ft 



FIGURE 20.-Tram duty cycle test course. 



the overloads tripping in the reverse 
direction and not the forward. The over- 
loads were adjusted to higher settings 
and the tripping problem was eliminated. 



These test results indicate that the CBSM 
has a tram cycle adequate for in-mine 
belt moves. Table 8 lists the results of 
the duty cycle test. 



TABLE 8. - Tram duty cycle test results 



Cycle 


Tramming on 


level 


Tramming up 


grade 


Hydraulic oil 




Voltage, V dc 


Current, A 


Voltage, V dc 


Current, A 


temperature, °F 


C 1 ) 

1 


135 
125 
119 
118 
117 
115 
115 
114 
113 
110 
107 
125 


NAp 

230-270 

230-260 

250 

250-260 

245-270 

250-300 

250-270 

240 

240 

245 

NAp 


NAp 

106 

104 

NM 

98 

100 

96 

94 

92 

88 

81 

NAp 


NAp 
520-590 
530-560 
540-560 
560-580 
545-590 
520-580 
540-580 
500-540 
530-570 
550-580 

NAp 


NAp 
131 


2 


137 


3 

4 

5 


NM 
149 
136 


6 

7 


126 
138 


8 


NM 


9 


NM 


10 


NM 


C 1 ) 


NAp 



NAp Not applicable. NM Not measured. 



Open circuit, 



25 



BELT WINDER TIME STUDY 

The objective of the belt winder time 
study was to determine the time required 
to perform the steps necessary to connect 
a belt to the belt winder reel and reel 
the belt onto the reel. The steps in- 
volved in this operation are as follows: 

o Latch winder drum. 

o Pay out cable from winder. 

o Install center drum on belt. 



note was that a single winder motor oper- 
ating on high pressure would not wind 
the belt up more than a few feet. It 
proved necessary to use the dual motors 
to wind the belt onto the reel. Use of 
dual motors on low pressure was not 
tested. Figures 21 through 23 show the 
belt winder system. 

The results of the time study indicate 
that the CBSM is capable of winding a 
belt on the reel for transport. The 
study also indicates that this procedure 
can be accomplished in a quick and safe 
manner. 



o Reel in cable. 

o Disengage winder drum latch. 

o Reel belt on winder drum. 

Table 9 lists the results of this time 
study. 

For this test, no attempt was made to 
simulate in-mine conditions. The belt 
was already double lapped to begin the 
study. As can be seen from the study re- 
sults, it took 3 min 45 s for the entire 
procedure to be performed. One item of 



TABLE 9. - Belt winder time study 
results, seconds 

Activity Time 

Latch drum NAp 

Pay out cable NAp 

Install center drum on belt 105 

Reel in cable 50 

Disengage drum latch NAp 

Reel belt on winder drum 70 

Total 225 

NAp Not applicable. 



SUMMARY 



The Bureau of Mines, through a contract 
with Tractor MBA, developed a self- 
contained, rubber-tired, battery-powered 
vehicle capable of handling, storing, and 
transporting conveyor belting, wire rope, 
and associated structures. The machine 
was tested underground in two mines in 
West Virginia and one mine in eastern 
Kentucky, but for very short periods. 
Because of short testing periods at each 
of these mines, the in-mine evaluation of 
the CBSM was inconclusive. The CBSM, 
therefore, was brought to the METF for an 
extensive surface test and evaluation. 
Highlights of the surface test program 
and evaluation follow: 

o The battery power system capability 
to power the CBSM was measured and found 
to be adequate. 

o The thermal stability of the CBSM's 
hydraulic system was investigated. 



Results indicated that the design of the 
hydraulic system is acceptable. 

o Speed tests were performed on the 
CBSM. The speed of the CBSM is within 
design specifications and suitable for 
in-mine use. 

o Braking tests were performed on the 
CBSM. Tests indicate that the braking 
system is quite adequate. 

o Current draw tests indicated that 
the CBSM's electrical system performs to 
specifications. 

o Belt winder tests indicated that the 
CBSM's belt winder system will perform as 
designed with the added flexibility of 
being able to choose a variety of tension 
ranges for belt retraction and extension. 



26 



«^.. '-* ; '- , «, *"" " - ' „ /', 



Belt moving into CBSM 





FIGURE 21. -Belt winder system. 




Belt entering for winding 



FIGURE 22.-Belt pulled in ready to wind. 



27 



Batteries 









Beit 



Belt reel 



\ 



- 



FIGURE 23.-Wound belt. 



o The 
is more 
use. 



tram duty cycle of the CBSM 
than sufficient for in-mine 



o The belt winder system is a quick 
and safe system operating to design 
criteria. 



REPAIRS AND MODIFICATIONS 



Numerous repairs and modifications were 
made to the CBSM to correct problems ob- 
served during surface testing. A com- 
plete listing is contained in appendix B. 
The major repairs and modifications are 
described below. 

TRACTION MOTOR FAILURE 

During battery capability testing, the 
left traction motor failed. After the 
motor was disassembled, it was discovered 
that straps used to secure the motor 
armature windings in place had worked 
loose. During operation of the motor, 



the straps apparently fell out and per- 
mitted the armature windings to make con- 
tact with the motor frame or pole pieces. 
This caused a catastrophic failure of the 
motor. A check of the right traction 
motor indicated that the straps were also 
loosening and that a failure of this 
motor was imminent. The left traction 
motor was replaced and the right motor 
refurbished. This traction motor failure 
highlighted the need for overload protec- 
tion in the tram control circuit. This 
modification was made and is described in 
the following section. 



28 



TRAM ELECTRONICS MODIFICATIONS 



SERVICE BRAKES MALFUNCTION 



During the investigation of the trac- 
tion motor failure, a number of areas of 
concern were discovered in the tram con- 
trol package. It was found that there 
was no specific motor overload protec- 
tion, neither instantaneous or thermal. 
The protection built into the circuit was 
for the protection of the tram package 
electronic components and not the trac- 
tion motors. A current limiting circuit 
in the tram package would limit machine 
current to 850 to 950 A. The traction 
motors are rated at 212 A each. A ther- 
mistor device was also located near the 
tram package silicon controlled rectifier 
to prevent high-temperature damage to the 
unit. However, this would do little to 
protect the motors. The plugging relay 
in the circuit was found to be bypassed 
and the dynamic braking resistors were 
missing from the machine. 

In an effort to provide overload pro- 
tection for the motors, the circuitry for 
the tram package was revised to incorpo- 
rate both thermal and instantaneous over- 
load protection. The instantaneous over- 
load circuit was adjusted to trip at 150 
pet of full-load current. A new plugging 
relay and new braking resistor were also 
installed. The new overload protection 
is shown on the electrical schematic. 



During the checkout of the CBSM, it was 
discovered that the service brakes were 
not operating properly. Troubleshoot- 
ing of the system indicated that the 
brake valve would not operate properly 
because the brake cup could not retract 
far enough to clear the bleed orifice to 
let oil from the return line fill the 
master cylinder cavity. A thicker gasket 
was installed on the brake valve between 
the piston and cavity and this corrected 
the problem. 

HYDRAULIC PUMP REPLACEMENT 

Also during checkout of the CBSM, the 
pressure-compensated hydraulic pump mal- 
functioned. The pump would not provide 
the expected flow or pressure. Attempts 
to repair the pump with on-hand spare 
parts proved unsuccessful. No specific 
cause could be identified for the failure 
of the pump other than simple attrition. 
A replacement variable displacement pis- 
ton pump was installed and the hyudraulic 
system functioned properly. 

While attempting to operate the belt 
winder lock, it was found that it did not 
operate properly. Therefore, the mecha- 
nism was redesigned. Figure 24 shows the 
redesigned belt winder lock. 



CONCLUSIONS 



Although the in-mine testing of the 
CBSM in three different underground mines 
of West Virginia and Kentucky and surface 
testing at the Bureau's METF were brief, 
the CBSM was operated enough to suggest 
the following design changes to improve 
its performance: 



o Reduce overall size of the CBSM to 
improve its capability to turn sharp 
tight corners in underground mines. 

o Fabricate the worktable with a 
lighter material for easier underground 
handling. 



o Consolidate and centralize all con- 
trols for one-person operation. 



o Increase the power of the belt 
winder. 



o Redesign the belt winder to accommo- 
date belts and drums of different lengths 
and sizes respectively; as in some under- 
ground mines, the belt is moved every 200 
ft or more. The redesign shall permit 
the removal of the wound belt in coiled 
configuration for storage. 



o Design belt guides to align the belt 
on the reel as it is being wound. 

o Reduce the power of the wire rope 
winches. 



29 




-M- 





/ 



Belt winder lock 



FIGURE 24.-Belt winder lock. 



o The CBSM was tested for very short 
periods underground and thus its in-mine 
evaluation on performance remained incon- 
clusive. It is, therefore, recommended 
to test this machine in an underground 



mine in a production mode for an extended 
period to evaluate its performance and 
rate of reduction of injuries related to 
belt moves. 



REFERENCES 



1. Coal 
rectory of 
p. 35. 

2. Eirls 
veyor Belt 



Mining. Seventh 
New Technology. 



Annual Di- 
Feb. 1985, 



J. L. Development of a Con- 
Service Machine (contract 
J0333926, Tracor, MBA). BuMines OFR 78- 
84, 1983, 109 pp.; NTIS PB 84-184845. 

3. Mayercheck, W. D. Coal Extraction, 
Transportation and Logistics Technology 
for Underground Mining. Pres. at SME/ 
AIME Of f-the-Record Meeting, Monroeville, 
PA, Nov. 11, 1985; 14 pp.; available upon 
request from W. D. Mayercheck, BuMines, 
Pittsburgh, PA. 

4. . Overview of Advanced Under- 
ground Coal Extraction and Transportation 



Equipment. Pres. at BuMines Open Indus- 
try Briefing, Monroeville, PA, Jan. 15, 
1985; available upon request from W. D. 
Mayercheck, BuMines, Pittsburgh, PA. 

5. Mayercheck, W. D. Overview of Con- 
veyor Haulage Research Projects To In- 
crease Productivity. Pres. at BuMines 
Open Industry Briefing on Mine Conveyor 
Haulage Safety and Productivity, Pitts- 
burgh, PA, July 19, 1983, and Denver, CO, 
July 21, 1983; available upon request 
from W. D. Mayercheck, BuMines, Pitts- 
burgh, PA. 

6. U.S. Bureau of Mines. Conveyor 
Belt Service Machine. Technol. News, No. 
206, Aug. 1984, 2 pp. 



30 



APPENDIX A.~ CONVEYOR BELT SERVICE MACHINE SPECIFICATIONS 

Main frame, overall length 275 in. 

Main frame, overall width 127 in. 

Wheelbase 104 in. 

Battery end overhang 73 in. 

Hitch end overhang 93.5 in. 

Tire size 10.0 by 15. 

Estimated weight 28,000 lb. 

Inside turning radius 9.5 ft. 

Outside turning radius 22.75 ft. 

Battery power 128 V, 680 A/h. 

Traction drive Two 30 hp at 1,750 r/min 120 V, series wound. 

Traction drive gear box 1 speed, 1.668:1 ratio. 

Braking Built-in park brake end service brake. 

Wheel drive 4 required. 

Steering capability ±22.5°. 

Load carrying capacity 10,000 lb each wheel. 

Overall gear reduction 28.98:1. 

Traction drive controller Silicon controlled rectifier, 1,000 A, 2 motor, 

with braking. 

Maximum drawbar capability 16,000 lb (equivalent to 50 pet fully loaded 

grade ability). 

Ground speed at 2,000 r/min 4.14 mi/h motor speed. 

Parking brake 50,000 fflbf at wheel drive. 

Steering system 4-wheel, full power, hydraulic, closed center, 

non-load reaction. 

Drive motor 20 hp at 1,800 r/min, 120 V dc, compound wound. 

Pump 20 gal/min at 1,500-psi pressure compensated, 

variable displacement piston pump. 

Hydraulic reservoir 18.7 gal. 

Filter 10 pm, throw-away, NAPA No. 1551. 



31 



Pneumatic system 

Drive Hydraulic motor. 

Compressor 2 stage, 5 hp , 20 ft 3 /min at 100 psi. 

Receiver 7.5 gal. 

Operating range 80 to 100 psi. 

Wire Rope Winders 

Drive Hydraulic motor. 

Maximum tension 6,000 lb. 

Maximum winding speed 60 r/min. 

Type Planetary gear reduction. 

Double-Lapped Belt Winder 

Primary drive Hydraulic motor. 

Gear reduction Enclosed spur gear. 

Maximum speed 50 r/min. 

Maximum tension 1,400 lb at 1,500 psi. 

Secondary drive Hydraulic motor. 

Maximum speed 50 r/min. 

Maximum tension 2,000 lb at 1,500 psi. 

Slat Conveyor 

Drive Hydraulic motor. 

Conveyor chain tension 6,000 lb at 1,500 psi. 

Maximum speed 20 r/min. 

Lift travel 6 in. 

Lift Hydraulic cylinder. 

Lift capacity 5,000 lb at 1,500 psi. 

Tail Section Hitch 

Type Hydraulic cylinder. 

Lift capability 2,000 lb per side at 1,500 psi. 

Lift control Individual. 

Lift height 10 in. 



32 



APPENDIX B. — CONVEYOR BELT SERVICE MACHINE 
REPAIRS AND MODIFICATIONS 



Date Repairs and modifications 

08/85 Repaired electric solenoid valve 
that actuates pneumatic system. 

10/85 Repaired coil of 2P contactor. 

10/85 Rebuilt 175-A, 600-V fuse holder. 

10/85 Replaced 2P contactor contacts. 

10/85 Rewired hydraulic control compartment, 

12/85 Replaced battery cables. 

04/86 Reconditioned right traction motor 
and hydraulic pump motor. 

08/86 Installed new left traction motor. 

08/86 Installed new regulator on pneumatic 
system. 

08/86 Replumbed hosing in operator's 
compartment. 

08/86 Replumbed brakes hydraulics. 

08/86 Repaired service brakes. 

08/86 Replumbed conveyor hydraulics. 

08/86 Replaced coil in hydraulic system 
bypass solenoid. 

08/86 Replaced auxiliary contact on 2P 
contactor. 

09/86 Installed new hydraulic pump. 

09/86 Installed new overloads in tram 
controlled circuit. 

09/86 Redesigned belt winder lock. 

10/86 Replaced belt winder sprocket and 
chain. 

11/86 Replaced belt winder coupling. 

U.S. GOVERNMENT PRINTING OFFICE: 1988 — 547-000/80,061 



Reason 



Valve malfunction. 

Coil case split and coil lead. 

The fuse holder would not accommo- 
date new ordered for CBSM. 

Contacts had welded together. 

Miswiring was causing shorts. 

Existing cables had shorted out. 

Major performance had deteriorated. 

Motor failed. 

Existing regulator malfunctioned. 



Existing hose routing did not leave 
room for operator. 

Brakes were plumbed incorrectly. 

The brake valve was not operating 
properly. 

Conveyor was plumbed incorrectly. 

Coil shorted out and prevented 
startup of hydraulic system. 

Contact malfunctioned and caused 
175-A fuse to blow in hydraulic 
pump control box. 

Original pump failed. 

Original circuit did not contain 
any motor protection. 

Original design did not work. 

Components failed. 



Do. 



INT.-BU.OF MINES,PGH.,PA. 28748 



o c 



U.S. Department of the Interior 
Bureau of Mines— Prod, and Distr. 
Cochrans Mill Road 
P.O. Box 18070 
Pittsburgh. Pa. 15236 



OFFICIAL BUSINESS 
PENALTY FOR PRIVATE USE. J300 



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